Pd nanoparticle and molecular Pd2+ leaching pathways for a strongly acid versus strongly basic resin supported Pd nanoparticle catalyst in Suzuki coupling

Vaerenbergh, Beau Van; Lauwaert, Jeroen; Vermeir, Pieter; Clercq, Jeriffa De

doi:10.1016/j.cej.2019.05.197

Cited by 48 publications

(37 citation statements)

References 86 publications

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“…Also, a significantly increased amount of leached palladium was detected in the filtrate in this case (Table , test h). Since the reaction between palladium NPs and aryl iodide (oxidative addition) is known to promote molecular palladium leaching, this result supports the hypothesis that only the molecular palladium species possess homogeneous catalytic activity under the reaction conditions.…”

Section: Resultssupporting

confidence: 79%

“…The only observed changes were associated with the loss of loosely attached larger particles of sizes≥100 μm, which did not undergo sintering during the 3d printing process due to their size (Figure ). Having verified mechanical durability of the produced catalyst under the reaction conditions, we next turned to mechanistic studies of the reaction, since sigmoidal kinetics can indicate pseudo‐homogeneous catalysis, taking place in solution after the true catalyst has leached from the solid phase pre‐catalyst …”

Section: Resultsmentioning

confidence: 99%

“…However, the analysis of the palladium content in solution (Table and discussion below in section 4.2) indicated that only a fraction of leached palladium was trapped by PVPy. It must be considered that palladium may leach in the form of coordination compounds (molecular leaching by dissociation of NPs) and soluble NPs (NP leaching by detachment from the support) . While PVPy effectively binds the molecular species, palladium NPs may remain in solution.…”

Section: Resultsmentioning

confidence: 99%

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3D Printed Palladium Catalyst for Suzuki‐Miyaura Cross‐coupling Reactions

et al. 2020

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Selective laser sintering (SLS) 3d printing was utilized to manufacture a solid catalyst for Suzuki-Miyaura cross-coupling reactions from polypropylene as a base material and palladium nanoparticles on silica (SilicaCat Pd 0 R815-100 by SiliCycle) as the catalytically active additive. The 3d printed catalyst showed similar activity to that of the pristine powdery commercial catalyst, but with improved practical recoverability and reduced leaching of palladium into solution. Recycling of the printed catalyst led to increase of the induction period of the reactions, attributed to the pseudo-homogeneous catalysis. The reaction is initiated by oxidative addition of aryl iodide to palladium nanoparticles, resulting in formation of soluble molecular species, which then act as the homogeneous catalyst. SLS 3d printing improves handling, overall practicality and recyclability of the catalyst without altering the chemical behaviour of the active component.

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Section: Resultssupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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3D Printed Palladium Catalyst for Suzuki‐Miyaura Cross‐coupling Reactions

et al. 2020

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“…8a), suggesting the signi cant challenge of this reaction condition to catalyst stability. Notably, the Pd contents in reaction solutions were tested by ICP-MS to be 5.5%-91% of the total Pd when treating different supported Pd catalysts with the initial reactants for 4 h in the absence of CsF (Washing Test) or keeping yield of A at low levels (Supplementary Table 3) 14 , however, only a very small portion of Pd remained in solution after the completion of the reactions (Table 1). These results clearly demonstrate the ''Cocktail" type nature of supported Pd-catalyzed carbonylation reactions, in which a Pd dissolution and redeposition process is involved 12 .…”

Section: Resultsmentioning

confidence: 99%

“…Typically, the detachment of Pd from the catalysts by catalytic interaction [10][11][12] , such as the oxidative addition of aryl halides (ArX) to Pd(0) species, initiates the reactions of C-C bond formation in solution 13,14 , and the redeposition of the regenerated Pd(0) species from reductive elimination back onto the support after the completion of the reaction recovers the supported Pd 15 . However, the regenerated Pd(0) species are very unstable and tend to aggregate either in reaction solution or in the process of redeposition, yielding a catalyst quite different from the fresh one [16][17][18] , and then resulting in a decline in the catalytic activity and undesirable recyclability, which poses a major issue for the practical application of supported Pd catalysts in solid-liquid catalysis.…”

Section: Introductionmentioning

confidence: 99%

Enhancing stability by trapping palladium inside N-heterocyclic carbene-functionalized hypercrosslinked polymers for heterogeneous C-C bond formations

Yue

Xing

Sun

et al. 2020

Preprint

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Catalyst deactivation caused by the aggregation of active metal species in the reaction process poses great challenges for practical applications of supported metal catalysts in solid-liquid catalysis. Herein, we developed a hypercrosslinked polymer integrated with N-heterocyclic carbene (NHC) as bifunctional support to stabilize palladium in heterogeneous C-C bond formations. This polymer supported palladium catalyst exhibits excellent stability in the one-pot fluorocarbonylation of indoles to four kinds of valuable indole-derived carbonyl compounds in cascade or sequential manner, as well as the representative Suzuki-Miyaura coupling reaction. Stabilizing mechanism investigations disclose that this catalyst displays a molecular fence effect in which the coordination of NHC sites and confinement of polymer skeleton contribute together to stabilize the active palladium species in the reaction process. This work provides new insight into the development of supported metal catalysts with high stability and will also boost their efficient applications in advanced synthesis.

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Bio‐Inspired Cu/Pd Bimetallic Catalysts Facilitating One‐Pot Relay Catalysis of Homo‐Couplings of Arylboronic Acids

Huang,

Shan,

Huang

et al. 2024

Applied Organom Chemis

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Inspired by the multienzymatic relay catalysis in nature, herein, we reported a pioneering bio‐inspired Cu/Pd bimetallic composite microspheres (Cu/CMC@Pd/C) as a simple and efficient relay catalyst for the homo‐coupling of arylboronic acids. In this composite, Pd/C was encapsulated by Cu(II)‐crosslinking carboxymethyl cellulose (Cu/CMC). Cu/CMC@Pd/C microspheres were easily achieved by adding a mixture solution of Pd/C and carboxymethyl cellulose into a Cu(II) solution through an ion exchange reaction between carboxylate groups of CMC and Cu(II) ions. The morphology and composition of the as‐prepared Cu/CMC@Pd/C microspheres were well characterized using various analytical tools such as FT‐IR, XRD, XPS, SEM, TEM, elemental mapping, EDS, and ICP‐AES. The analysis indicated that the composite microspheres have a porous structure and Pd/C is uniformly distributed within the interior of the composite microspheres. The porous structure facilitates mass transfer of the substrate and increases the contact area of the catalyst, thus improving reaction efficiency. The performance of Cu/CMC@Pd/C microspheres was assessed in the homo‐coupling of arylboronic acid for the synthesis of symmetric biaryl without the need for an aryl halide as a partner. This process mimics a multienzyme catalysis through a relay Cu(I)‐catalyzed halogenation of one portion of arylboronic acid and a Pd(0)‐catalyzed Suzuki–Miyaura cross‐coupling between the in situ generated aryl halide and another portion of arylboronic acid. The results showed that this bio‐inspired Cu/CMC@Pd/C has excellent relay catalytic activity with tolerance of broad functional groups, producing the desired symmetrical biaryls in excellent yields within a short reaction time under mild conditions. Moreover, the catalyst can be easily recovered through simple filtration and still has good catalytic activity after six cycles. Consequently, this innovative pseudo‐homogeneous Cu/Pd relay catalyst emerges as a convenient and efficient alternative for the synthesis of asymmetric biaryls.

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Pd nanoparticle and molecular Pd2+ leaching pathways for a strongly acid versus strongly basic resin supported Pd nanoparticle catalyst in Suzuki coupling

Cited by 48 publications

References 86 publications

3D Printed Palladium Catalyst for Suzuki‐Miyaura Cross‐coupling Reactions

3D Printed Palladium Catalyst for Suzuki‐Miyaura Cross‐coupling Reactions

Enhancing stability by trapping palladium inside N-heterocyclic carbene-functionalized hypercrosslinked polymers for heterogeneous C-C bond formations

Bio‐Inspired Cu/Pd Bimetallic Catalysts Facilitating One‐Pot Relay Catalysis of Homo‐Couplings of Arylboronic Acids

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